Vision testing system

ABSTRACT

A method and apparatus are provided for testing the vision of a human subject using a series of eye tests ( 310 ). A test setup procedure ( 312 ) is run to adjust the settings of a display device ( 1914 ) such that graphic objects displayed on the device ( 1914 ) conform to a pre-defined appearance. A series of preliminary tests ( 314 ), static tests ( 316 ) and dynamic tests ( 318 ) are displayed on the device ( 1914 ), and the responses of the subject are recorded. The tests ( 310 ) may be run remotely, for example over the Internet. No lenses are required to run the tests ( 310 ).

FIELD OF THE INVENTION

[0001] The present invention relates generally to vision testing ofhuman subjects, and in particular, to the lensless testing of visionusing video display screens.

BACKGROUND ART

[0002] Vision is involved intimately with almost every aspect of aperson's daily life. If a person's vision deteriorates then usually sodoes the person's quality of life.

[0003] Vision can be divided into three conceptual layers, seengenerally in FIG. 1. An optical layer 100 provides for the focusing oflight onto a photosensitive layer of tissue at the back of the eye,called the retina. A functional layer 102 (formed by the retina)contains photosensitive cells which can detect various colours, motionand form, and convert these to nervous impulses which are sent to thebrain. The third layer is a perceptual layer 106 which is a part of thebrain that constructs a picture from the light information sent from theeyes.

[0004] During the last century, many tests have been developed tomeasure aspects of the vision process, and three groups ofprofessionals, optometrists, ophthalmologists and neurologists, have hadthe responsibility divided between them for carrying out the tests andtreating the problems involved.

[0005] Optometrists are scientifically qualified and in general measureand treat problems associated with the optical layer 100. Asoptometrists are usually the first to deal with a patient having avision problem, optometrists often detect problems in the functional andperceptual layers 102,106. If a pathological problem arises in area 102or 106 optometrists generally refer patients to the professionals bestqualified to treat these problems. Ophthalmologists are medicallyqualified and normally measure and treat problems involving both theoptical layer 100 and the functional layer 102. This group ofprofessionals will typically diagnose and treat diseases of the eye.Problems occurring in the perceptual layer 106 caused by other diseasesaffecting the visual process are usually referred to a neurologist.Neurologists are psychiatrically and medically qualified, and treat theproblems occurring at the perceptual layer 106 when the vision processis affected by other perturbing abnormalities in the patient's brain

[0006] It is routine for people experiencing some vision problem tovisit an optometrist to have their eyes examined. The equipment used bythe optometrist for examination is mainly lens-based. Since suchequipment is often heavy, bulky and very sensitive, it is generally notsuitable for transport. Such equipment is often quite expensive.Consequently people who lack mobility, or who live a long way fromcities or large towns, have been disadvantaged through lack ofoptometric servicing. When optometrists do travel, generally only asmall number of lenses are used for diagnostic purposes, and as such,the examination conducted may not be as thorough as one performed withthe aid of the typical equipment mentioned above.

[0007] It is therefore desirable for optical examinations to beperformed without reliance upon bulky, generally immobile and expensiveequipment.

SUMMARY OF THE INVENTION

[0008] It is an object of the present invention to substantiallyovercome, or at least ameliorate, one or more disadvantages of existingarrangements.

[0009] According to a first aspect of the invention there is provided amethod for testing vision of a human subject, said method comprising thesteps of:

[0010] (a) adjusting at least one setting of a display device such thata sequence of graphic objects displayed on said display device conformsto a pre-defined appearance;

[0011] (b) displaying said sequence of graphic objects on said displaydevice to test the visual functioning of the human subject,

[0012] (c) recording at least one action of the human subject performedin response to the display of said sequence of graphic objects;

[0013] (d) calculating from said recorded actions at least one aspect ofthe visual functioning of the subject; and

[0014] (e) calculating at least one corrective lens prescription for thehuman subject from said at least one aspect of the visual functioning ofthe subject.

[0015] According to a second aspect of the invention there in provided acomputer program element comprising computer program code means to makea computer execute a procedure to:

[0016] adjust at least one setting of a video display of said computersuch that a sequence of graphic objects displayed on said video displayconforms to a pre-defined appearance;

[0017] display said sequence of graphic objects on said video-display totest the visual functioning of said human subject,

[0018] record at least one action of said human subject performed inresponse to the display of said sequence of graphic objects;

[0019] calculate from said recorded actions at least one aspect of thevisual functioning of said subject; and

[0020] calculate at least one corrective lens prescription for the humansubject from said at least one aspect of the visual functioning of thesubject.

[0021] According to a third aspect of the present invention there isprovided a computer readable medium, having a program recorded thereon,where the program is configured to make a computer execute a procedureto:

[0022] adjust at least one setting of a video display of said computersuch that a sequence of graphic objects displayed on said video displayconforms to a pre-defined appearance;

[0023] display said sequence of graphic objects on said video display totest the visual functioning of said human subject,

[0024] record at least one action of said human subject performed inresponse to the display of said sequence of graphic objects;

[0025] calculate from said recorded actions at least one aspect of thevisual functioning of said subject; and

[0026] calculate at least one corrective lens prescription for the humansubject from said at least one aspect of the visual functioning of thesubject.

[0027] According to a fourth aspect of the present invention there isprovided a system for the testing of vision in a human subject, saidsystem comprising:

[0028] a) a server having:

[0029] a first memory for storing an application program and one or moretest results from visual testing of a human subject;

[0030] means for receiving said one or more test results;

[0031] means for transmitting said application program;

[0032] means for processing said one or more test results to calculateat least one aspect of the visual functioning of the human subject; and

[0033] means for calculating at least one corrective lens prescriptionfor the human subject from said at least one aspect of the visualfunctioning of the subject; and

[0034] b) a client computer having:

[0035] a display device for displaying a sequence of graphic objects tothe human subject;

[0036] means for receiving said application program;

[0037] means for running said application program to adjust at least onesetting of said display device such that said sequence of graphicobjects displayed on said display device conforms to a pre-definedappearance;

[0038] means for recording said one or more test results of the humansubject in response to the display of said sequence of graphic objects;and

[0039] means for transmitting said one or more test results to saidserver.

[0040] According to a further aspect of the present invention there isprovided a method of standardising the appearance of visual objectsdisplayed on a video display, the method comprising the steps of:

[0041] installing an application program file on a computer;

[0042] displaying said visual objects on said video display connected tosaid computer;

[0043] requesting a person viewing said video display to confirm thesize of at least one of said visual objects;

[0044] requesting the person to confirm whether a specified one of saidvisual objects is visible; and

[0045] said application program file utilising the responses of theperson to said requests to adjust the relative outputs of the coloursused in displaying said visual objects and the relative dimensions ofsaid visual objects.

[0046] According to a further aspect of the present invention there amethod for measuring the vision of a human subject, said methodcomprising the steps of:

[0047] displaying on a display device a first test to check whether thevision of said subject is within a measurement range of said method;

[0048] displaying on said display device a second test to determine arequired sensitivity of said method;

[0049] selecting, based on responses of said subject to said first andsecond tests, further tests to display on said display device to measurean optical power of one or both eyes of said subject; wherein saidfurther tests are selected from the group consisting of:

[0050] tests of visual acuity;

[0051] tests of spherical power;

[0052] tests of cylindrical power;

[0053] tests for astigmatism; and

[0054] tests for near visual acuity;

[0055] and wherein said subject views said first test, said second testand said further tests without lenses being interposed between saiddisplay device and said subject.

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] A number of embodiments of the present invention will now bedescribed with reference to the drawings in which:

[0057]FIG. 1 shows the conceptual layers of the visual system;

[0058]FIG. 2 shows a data flow structure illustrating how the visionstests incorporating the embodiments are distributed and analysed;

[0059]FIG. 3 shows the basic layout of an Internet web page on which thevision tests are presented;

[0060]FIG. 4 shows a schematic data flow diagram illustrating theinterrelationship between the vision tests;

[0061]FIG. 5 shows a more detailed data flow diagram of the sequence ofthe vision tests;

[0062]FIG. 6 shows an example of a preliminary test result as displayedon a computer screen;

[0063]FIG. 7 shows a schematic data flow diagram illustrating theanalysis of optical layer problems by a diagnostic assistant program;

[0064]FIG. 8 shows a schematic data flow diagram illustrating how thediagnostic assistant program analyses data concerning the functional andperceptual layers;

[0065]FIG. 9 shows a display used in visual acuity testing;

[0066]FIG. 10A shows a visual object used in testing of astigmatism;

[0067]FIG. 10B illustrates the effects of astigmatism;

[0068]FIGS. 10C and 10D illustrate the functioning of a firstastigmatism test;

[0069]FIG. 10E illustrates the functioning of an alternative embodimentof the first astigmatism test;

[0070]FIG. 11 shows a boxed C object used in visual acuity testing;

[0071]FIG. 12A shows a visual object used in assessing astigmatism;

[0072]FIG. 12B shows two further objects used in the assessment ofastigmatism;

[0073]FIG. 12C shows alternative objects used in the assessment forastigmatism;

[0074]FIG. 12D shows alternative objects used in the assessment forastigmatism;

[0075]FIG. 12E shows alternative objects used in the assessment forastigmatism;

[0076]FIGS. 12F and 12G show two example patterns used in testing grossvisual acuity,

[0077]FIGS. 12H12I and 12J show three example patterns used in testingvisual acuity,

[0078]FIG. 12K shows a test window used for testing near visual acuity;

[0079]FIG. 13 shows visual objects used in assessing peripheral vision;

[0080]FIG. 14—shows an image used in assessing macula integrity;

[0081]FIGS. 15A, 15B and 15C show visual objects to be displayed on avideo screen in order to test a child's visual performance;

[0082]FIG. 16 shows visual objects used in assessing a patient'sbinocular vision;

[0083]FIG. 17 shows objects used in assessing a patient's ability tofuse images;

[0084]FIG. 18 shows visual objects used in the testing of stereopsis;

[0085]FIG. 19 shows a computer system on which the vision testing may becarried out;

[0086]FIG. 20A shows a computer screen display for thecontrast/brightness tests;

[0087]FIG. 20B shows a computer screen display for the colour red test;

[0088]FIG. 20C shows a computer screen display for the colour greentest; and

[0089]FIG. 20D shows a computer screen display for the colour blue test.

[0090]FIG. 20E shows a diagrammatic view of a computer screen display ofthe glare balance test.

[0091]FIG. 20F shows visual objects for size calibration test.

DETAILED DESCRIPTION INCLUDING BEST MODE

[0092] Vision testing in an optometry clinic normally involves theextensive use of lenses. Disclosed herein is a vision analysis systemthat does not require the use of lenses. The elimination of the lensesis accomplished by a computer-based vision testing system incorporatingprograms which allow the vision testing to be carried out on a videodisplay unit, such as a computer monitor, and which may be performed ata location remote from an optometrist.

[0093] Remote vision testing in this disclosure has two primecomponents; the vision test, and the vision diagnosis. The vision testmay be performed using remote optometric equipment formed by a computeroperated by the patient or an assistant. The computer is typicallyconnected to a network such as the World Wide Web (WWW) to allow accessto a further computer at which the diagnostic evaluation is undertaken.

[0094] The method of vision testing described herein is preferablypracticed using a conventional general-purpose computer system 1900,such as that shown FIG. 19 wherein the processes of FIGS. 2 to 18 may beimplemented as software, such as an application program executing withinthe computer system 1900. In particular, the steps of the method ofvision testing are effected by instructions in the software that arecarried out by the computer. The software may be divided into twoseparate parts; one part for carrying out the vision testing methods;and another part to manage a user interface between the vision testingmethods and the patient. The software may be stored in a computerreadable medium, including the storage devices described below, forexample. The software is loaded into the computer from the computerreadable medium, and then executed by the computer. A computer readablemedium having such software or computer program recorded on it is acomputer program product The use of the computer program product in thecomputer preferably effects an advantageous apparatus for vision testingin accordance with the embodiments of the invention.

[0095] The computer system 1900 comprises a computer module 1901, inputdevices such as a keyboard 1902 and mouse 1903 and output devicesincluding a printer 1915 and a display device 1914. AModulator-Demodulator (Modem) transceiver device 1916 is used by thecomputer module 1901 for communicating to and from a communicationsnetwork 1920, for example connectable via a telephone line 1921 or otherfunctional medium. The modem 1916 can be used to obtain access to theInternet, and other network systems, such as a Local Area Network (LAN)or a Wide Area Network (WAN).

[0096] The computer module 1901 typically includes at least oneprocessor unit 1905, a memory unit 1906, for example formed fromsemiconductor random access memory (RAM) and read only memory (ROM),input/output (I/O) interfaces including a video interface 1907, and anI/O interface 1913 for the keyboard 1902 and mouse 1903 and optionally ajoystick or microphone (not illustrated), and an interface 1908 for themodem 1916. A storage device 1909 is provided and typically includes ahard disk drive 1910 and a floppy disk drive 1911. A magnetic tape drive(not illustrated) may also be used. A CD-ROM drive 1912 is typicallyprovided as a non-volatile source of data. The components 1905 to 1913of the computer module 1901, typically communicate via an interconnectedbus 1904 and in a manner which results in a conventional mode ofoperation of the computer system 1900 known to those in the relevantart. Examples of computers on which the embodiments can be practisedinclude IBM-PC's and compatibles, Sun Sparcstations or alike computersystems evolved therefrom.

[0097] Typically, the application program of the preferred embodiment isresident on Intermediate storage of the program and any data fetchedfrom the network 1920 may be accomplished using the semiconductor memory1906, possibly in concert with the hard disk drive 1910. In someinstances, the application program may be supplied to the user encodedon a CD-ROM or floppy disk and read via the corresponding drive 1912 or1911, or alternatively may be read by the user from the network 1920 viathe modem device 1916. Still further, the software can also be loadedinto the computer system 1900 from other computer readable mediumincluding magnetic tape, a ROM or integrated circuit, a magneto-opticaldisk, a radio or infra-red transmission channel between the computermodule 1901 and another device, a computer readable card such as aPCMCIA card, and the Internet and Intranets including emailtransmissions and information recorded on websites and the like. Theforegoing is merely exemplary of relevant computer readable media Othercomputer readable media may be practiced without departing from thescope and spirit of the invention.

[0098] The method of vision testing may alternatively be implemented indedicated hardware such as one or more integrated circuits performingthe functions or sub functions of vision testing. Such dedicatedhardware may include graphic processors, digital signal processors, orone or more microprocessors and associated memories.

[0099]FIG. 2 shows a network of data flow paths 200 for part of thevision testing system, typically operating from within or associatedwith the host computer 214, which may be formed by a server arrangementof computers. Software which enables the diagnostic evaluation to takeplace is stored on a component computer system 214. The computer system214 includes a web host 216, an information management system to supportthe functions of a technical manager 218, and an optometry manager 220.The technical manager 218 interacts with a technical information system222 to ensure smooth running of the system, computer maintenance,upgrades and security. The optometry manager 220 is linked to amarketing information system 238 and a sales information system 240 torelate clients vision problems with eye wear needs. The optometrymanager 220 is also linked to a clinical validation system 224, aclinical data base 226 and a diagnosis module 228 to oversee dataintegrity, test accuracy and authorise the release of the clinicalprescription results. Prior to release of the clinical results to theclient, the optometrist confirms with the accounts manager 234 that theservice has been performed and that payment has been receive& Theaccounts database 234 is in turn connected to the information system ofa bank 236 or other financial institution, thus allowing the automaticprocessing of financial transactions with patients.

[0100] When diagnostic evaluation data is received from a patient, thedata passes from the WWW 202 through a public telecommunications network(PTN) 212 to the host computer 214 where the data is passed by theoptometry manager 220 for processing by the clinical validation system224. Both the raw and the processed data are then stored in the clinicaldatabase 226. Test data from the clinical database 226 are passed to adiagnostic module 228, in which the data may either be analysedautomatically by a diagnostic assistant program 700, depicted in FIG. 7,or analysed by a legally registered optometrist. The results of thediagnosis are then tabulated as patient/client results 230, which arethen stored in the clinical database 226, and also forwarded to thepatient via an email system 232 operable via the PTN 212 and WWW 202.

[0101] The marketing information system 238 is linked to a salesinformation system 240 which transfers information to a supplyinformation system 242. The sales information system 240 and the supplyinformation system 242 are both linked to the accounts database 234.Goods that are disseminated via the supply information system 242 aresent to patients by surface mail 246, either by delivery via the postoffice or by courier.

[0102] The PTN 212 connects to the World Wide Web 202 either directlyvia standard telephone lines, or alternatively by an Integrated ServicesDigital Network (ISDN) 208. The PTN 212 can also link to the World WideWeb 202 via a radio communication system 210, a cellular telephonysystem 206 or a satellite communication system 204.

[0103] A patient gains access to the vision test diagnostic evaluationsystem by using the computer 1901 to log-on to the World Wide Web 202using a software application such as an Internet web browser whichenables the viewing of web pages. Examples of such; browsers includeInternet Explorer manufactured by Microsoft Corporation and NetscapeNavigator manufactured by Netscape Corporation. Using such tools, thepatient is able to connect to an Internet web site 300, architecturallyillustrated in FIG. 3, and operated by the web host 216 of FIG. 2. Thepatient will initially see a home page 302 which contains generalintroductory material. The home page 302 contains links to a furtherpage 304 which contains information about the company which provides thediagnostic evaluation system. The home page 302 also provides a link toa search page 306 which allows the patient to search the web site 300for documents containing selected words or patterns of words. If asearch is initiated, the results will be displayed as a further web page308. The home page 302 also contains a link to a web page 310 whichcontains more detailed introductory information about the eye testsavailable on the web host 216. Links are also provided to a web page 320which describes changes to the web site 300 and gives informationregarding press releases and media coverage. There is also a link to aVision Shop web page 322 where patients are able to purchase optometricgoods. The vision shop 322 has a link to an information web page 324which contains general information about the visual system, adescription of eye anatomy and eye diseases, a description the neurologyof vision, and simulated images of how the world appears to someone withvision problems.

[0104] If a patient elects to proceed with the diagnostic evaluation,the eye test web page 310 provides a link to a test set-up 312 whichcalibrates the video display 1914 used by the patient such that objectsdisplayed to the patient during the testing have a standardisedappearance. Once the test set-up 312 is complete, the patient mayproceed to web pages which interactively perform a series of preliminarytests 314, static tests 316 and dynamic tests 318.

[0105]FIG. 4 illustrates the sequence in which the eye tests 310 areperformed. The test setup 312 is a prerequisite, and performs variouscalibration steps. After this, a number of preliminary tests 314, statictests 316 and dynamic tests 318 are performed. Each set of tests 314,316 and 318 may be used to assess the vision of either a child patientor an adult patient. Child tests 402, 406, 410 are desirably preformedwith the assistance of a supervising adult. The adult tests 404, 408 and412 may be performed unassisted, but in general will be easier to runwith the help of an assistant.

[0106]FIG. 5 gives further detail of the eye tests 310. When the testset-up 312 is activated, there is a first load file step 502. The loadfile step 502 downloads a test file from the (server) computer system214 and loads the test file into (patient/client) computer system 1901where the test file is stored on the hard disk drive 1910. Havingcompleted the load file step 502, the patient is required to run aseries of calibration tests to standardise the vision testing. Thecalibration tests include a screen shape test 504, a screen size test506, a contrast and colour test 508, a glare test 509, and anenvironment test 510, the latter to ensure that the lighting conditionsin the room where the video display 1914 is situated will remainconstant during the course of the remaining tests.

[0107] The visual tests 314, 316, 318 will be described in greaterdetail below, but in summary, the preliminary test 314 includes a visualacuity test 512, and an astigmatism test 514 following which a page ofresults 516 is presented to the patient on the video dispaly 1914. Thestatic tests 316 include a prefilter test 517 to determine grosspathology and refractive error status, a history questionnaire 518concerning relevant facts of the patient's medical history, a grossvisual acuity discrimination test 519, a visual acuity test 520 using awhite background, a visual acuity test 522 on a red background, a visualacuity test on a green background 524, a visual acuity and pathologydetection contrast pattern test 525, astigmatism tests 526 and 527, atest for the possible presence of cataracts and other diseases 532, atest 534 of macula integrity, a test of peripheral vision 536 and a test538 of colour vision. If the patient is a child there may be two furthertests 528 and 530, the first to detect saccades and the second to detectvisual peripheral scanning skills. Tests 532 and 534, which test forpossible presence of cataracts and changes to the macula are used onlyin the case where the patient is an adult The dynamic tests 318incorporate four tests of binocular vision 540, 542, 544, 546. Each ofthe above-noted tests will now be described in greater detail.

[0108] Test File Download Routine

[0109] The object of the load file step 312 is to install an applicationprogram file on the patient's computer 1901 which is configured tointeract with the host computer 214, representative of the Web host 216.The application program file is in ActiveX document or Java format, orsuch similar computer language to allow operation as a hypertext-awaredocument in an Internet browser, such as Microsoft Internet Explorer orNetscape Navigator as mentioned above.

[0110] The file contains compiled software code configured tointeractively run the various tests mentioned above including a seriesof tests designed to calibrate the physical characteristics of thepatient's monitor 1914. The file also allows responses from the patientto be recorded for sending to the host computer 214 for analysis. Duringthe preliminary test, the application program file calculates anddisplays the test results for the patient to examine. When the static316 and dynamic 318 tests are performed, the file encrypts the resultsto ensure patient security, prior to the results being communicated tothe host computer 1950. Some or all of the tests may be carried out onthe host computer 1950 via the WWW 300 using Microsoft Active ServerPage (ASP) technology rather than the patient's computer 1901. Thisalternative is used for example where the patient does not wish to haveprograms loaded onto the patient's computer 1901, where there is a needfor extra security, or in cases where the tests can be more closelycontrolled.

[0111] Prior to the start of vision testing, it is necessary to assessthe operation of the patient's computer 1901 and associated display 1914to ensure appropriate calibration to afford a desired level of accuracyof the vision testing.

[0112] Screen Shape Test 504

[0113] Once the file is loaded on the patient's computer 1901, a page isdisplayed on the display 1914 to ensure that the display area of thedisplay 1914 has been adjusted to give a rectangular image with a smallstraight-edged border of black around the edges. If the display 1914cannot be adjusted to give a standard rectangular display, then amessage is displayed on the display 1914 advising the patient not tocontinue with the tests.

[0114] Screen Size Test 506

[0115] The eye tests 310 are based largely upon the patient's responsesto grey-scale and coloured images of known size. Since the size of theimages is likely to change with screen size and resolution, it isimportant to either standardise the screen size and resolution or toadjust the images displayed to be the correct size when displayed onvarious screen sizes and resolutions.

[0116] With typical personal computers, the screen resolution can befound by the test program directly interrogating the operating systemrunning on the computer 1901. Examples of operating systems includeWindows manufactured by Microsoft Corporation. The actual screen size ishowever, not recorded anywhere. To determine the screen size, a test hasbeen devised in which a line of programmed length is displayed on thedisplay 1914 by the test program, and the patient uses a ruler tomeasure the length of the line. The patient can then enter the measuredlength into the computer 1901, using the keyboard 1902 for example.Since the length of the line as seen on the display 1914 is dependentupon both the screen size and the resolution, by knowing either one ofthese values, the test program can calculate the other. Thus, havingobtained the screen resolution from the operating system, the screensize maybe readily found.

[0117] An alternative approach is to present the patient with a seriesof common images as shown in FIGS. 20F, 20G and 20H. These imagesinclude a square 2004 with sides of 10 cm, an image 2008 of a creditcard. It is noted that the image 2008 of the credit card shows theregistered trade mark “MasterCard” for illustrative purposes. Also shownis an image 2006 of a 3.5″ floppy diskette. The client can then use oneor more of a ruler, a, real credit card or a real floppy diskette laidagainst the images 2004, 2006 or 2008 displayed on the computer monitorscreen 1914 to measure whether the object is the same size as the object2004-2008 on the screen. If the real object differs in size from theimage 2004-2008 then the screen object is adjusted using the mousepointer 1903 until the images 2004-2008 are the same size as thecorresponding real objects. When the screen object 2004-2008 is the samesize as the real objects, the screen size and resolution can be fixed.

[0118] Another approach, where the resolution is set at 800×600 pixels,is to display an image to the patient that contains lines (or otherobjects) of different lengths. The test program then asks the patient touse the mouse pointer 1903 to click on a line that is, or is closest to,say, 10 cm long. The line which the patient selects is then used tocalculate the screen size.

[0119] Screen Contrast and Colour Test 508

[0120] It is important that the display 1914 is adjusted for both blackand white contrast and colour to ensure Fat the tests which aresensitive to contrast and/or colour are standardised and carried outcorrectly.

[0121] The screen brightness and contrast are usually adjusted by thepatient, while the relative intensity of the three colours used to makeup colour images is usually set during manufacture of the display 1914,or by electronics repair technicians.

[0122] The contrast/brightness of the display 1914 varies according tothe ambient brightness of the area (room) where the video display 1914is located. If the area has mixtures of natural light (daylight) andartificial light, the brightness/contrast may vary considerably.

[0123] To avoid having to adjust the display 1914 throughout the day,most computer users generally have the display 1914 adjusted for thebrightest part of the day, which means that the display 1914 is oftentoo bright at other times, causing colours to be washed out, and blacksto become grey.

[0124] The contrast and colour test 508 was developed to allow easyadjustment of both the contrast/brightness levels and the relativeoutputs of the three (red, green, blue) colours making up the colourimages seen on the display 1914. The test 508 provides a means ofadjusting the physical parameters of the video display 1914 by usingsoftware programming to a sensitivity of less than 15%.

[0125] The contrast/brightness test is a test pattern 800 composed ofseven squares 802, each having a differing grey-scale intensity rangingfrom pure white to black, as shown in FIG. 20A. The squares 802 arearranged from left to right on the video display 1914. The grey scalesare adjusted such that on a balanced video display 1914, the left sixgrey scale squares 804 should be seen, while the seventh square 806should be invisible.

[0126] If the seventh square is still visible, then the display 1914 istoo bright, and the patient is asked to reduce the brightness and/orcontrast using external controls provided on the video display 1914 soas to make the seventh square 806 disappear. If less than six squaresare seen then the patient is asked to adjust the brightness/contrastcontrols until the left six grey scale squares 804 can be seen.

[0127] The adjustment for the three primary colours (red, green andblue) is similar in that it uses seven coloured squares varying inintensity from the full colour to black. Each colour (red, green andblue) is separately adjusted, in a fashion similar to FIG. 20A, as seenin FIGS. 20B-20D.

[0128] It is most often necessary to increase the intensity of onecolour, as the three electron guns supplying the colours do not seem todegrade at the same rates.

[0129] The colour intensities are varied in a fashion that weights thefeinted colours more heavily than the brighter colours.

[0130] Any colour adjustments can be saved in the program memory 1906and used at a later stage to adjust images and backgrounds, to ensurethat the tests use standard colours.

[0131] Screen Glare Test 509

[0132] Before eye tests 314 preferably commence, the patient is alsorequired to measure or mark out three distances, 40 cm, 100 cm and 300cm, from the video display 1914, as the tests 314 will be carried outwith the patient's eyes positioned at predetermined distances from thevideo display 1914. These distances are important to ensure accuracy, asvisual acuity varies with test distance.

[0133] The glare from excessive reflected light from elsewhere in theroom environment may affect the ability of the patient to comfortablyview the computer display 1914 and obtain optimal test results. TheScreen Glare test 509 was developed to standardise room lighting,eliminate any reflected glare off the video monitor and to allowstandardised adjustments of both the contrast/brightness levels and therelative outputs of the three colours (red, green, blue). The test 509for excess glare is carried out using a visual object 2000, shown inFIG. 20E. The object 2000 consists of blue squares 2002 displayed onlighter blue background 2003. The squares 2002 are preferably 3 cm by 3cm with an RGB value of (0,0,122) and the RGB value of the background2003 is preferably (0,0,128). Although six squares are shown in FIG.20E, in a typical arrangement, 9 of the squares 2002 can be displayed.In this test the patient is asked to reduce the room lighting until allthe blue squares 2002 are visible. Sitting at the measured distance of300 cm, the patient is instructed to count the number of dark bluefilled squares 2002 on a lighter blue background 2003. If all squarescan be seen comfortably then the test is passed. If glare from somelight source in the immediate environment impairs the view of any of thesquares 2002, the patient is asked to adjust or block the offendinglight or reposition the computer display 1914 to correct the problem.

[0134] The patient is also asked to make sure that the room lightingconditions will remain unchanged during the tests.

[0135] The environment function 510 is a set of instructions relating toroom lighting, glare and measuring distances from the computer display1914.

[0136] Preliminary Tests 314

[0137] The preliminary tests 314 are of a screening nature, and involvea test for visual acuity 512 and a test for astigmatism 514. The tests314 are carried out by the patient and analysed by a program running onthe local computer 1901 to determine whether the patient's vision iswithin a normal range, or whether farther help is required.

[0138] Visual Acuity Test 512

[0139] The first of the visual efficiency tests is referred to as the“growing E” test and gives an indication of the functioning of theoptical layer 100 and functional layer 102. The test 512 is devised toobtain an accurate measure of the visual acuity of the patient's eyesand is run in an interactive fashion over the WWW 202. A correspondingtraditional test would normally be carried out in an optometry clinic byexamining fixed predetermined letter sizes on a standard letter chartThe interactive test 512 is more accurate than a wall chart, as itprovides a wider range of letter sizes (25 as compared with the usual9).

[0140] As seen in FIG. 9, the growing E test uses four black visualobjects 910 randomly displayed on a white background, each one similarto the alphabet letter E but rotated such that each letter faces up,down, left and right respectively, the direction being determined by thegaps formed by the three arms of the letter. These visual objects 910are referred to as E-objects. Each E object is displayed in black(RGB=0, 0, 0) on a white background (RGB=255, 255, 255).

[0141] A set of written instructions is displayed on the video display1914 indicating how the patient is to run the test 512, and how to setup the viewing distances. It is recommended that the tests should becarried out by two people, the patient and an assistant. It is alsopossible for the patient to do the test 512 unaided, but with a littlemore difficulty.

[0142] The test 512 involves the assistant staring the test 512 runningby using the mouse 1903 to press a Start button icon displayed on thevideo display 1914. The patient watches the E object 910 grow from asmall size to a very large size on the video display 1914. The sizepreferably ranges from 2 to 150 mm in growth increments of 2 mm. Whenthe patient can see the direction of the gaps in the letter E, thepatient asks the assistant to stop the growth of the E object 910 byclicking the mouse 1903 over a direction arrow button icon 920. If thedirection is correctly named by the patient the assistant records theresult. If the response is not correct, the test is repeated until threecorrect responses are made. The then current size of the E object 910 isrecorded.

[0143] Two controls are available to adjust the speed of the test 512.One such control adjusts the time delay interval between pressing theStart button and the start of the display of the E object 910. This isuseful if a patient conducts the test without the help of an assistant,as the delay allows enough time for the patient to get into the testposition before the test 512 starts. A delay of between 0.5 and 20seconds can be selected. The second speed control allows adjustment ofthe object growth speed. This is the time interval between display ofsuccessive B objects 910. This is useful if the patient has poor vision,as the test 512 will reach the larger objects more quickly. The objectgrowth speed can be varied from 0.5 to 5 seconds.

[0144] The test 512 is performed at two distances from the screen, 40cm, and either 300 cm or 100 cm, depending upon the patient's grossvisual efficiency. The testing distance is recorded for each test toindicate whether the patient's visual efficiency is measured at a normalor close distance. At each distance the test 512 is run for the left eyeand the right eye individually. Each run of the test 512 is repeatedthree times to obtain an average object size at which the directionarrow button icon 920 was actuated. This gives a measure as to visualfunction for close up tasks and for distance tasks. The size of the Eobject 910 viewed from a known distance is related to the visual acuity.Visual efficiency is expressed as a percentage of the visual acuityrelative to the visual acuity of normal eyesight. Visual efficiency forboth eyes (binocular visual efficiency) is calculated as a weightedaverage of the visual acuity as follows:

Visual efficiency=100×((3×(visual acuity of best eye)+(visual acuity ofworst eye))/4)%.

[0145] First Astigmatism Test 514

[0146] Astigmatism is a condition where a person's sight levels are inconstant conflict for distance and near vision, with the eye reaching apoint of equal blurring when neither distance nor close vision isperfectly clear. There is an irregularity to the optical surfaces of theeye that causes blurriness at all distances. The defect is similar tothe distortion seen when looking through a cylindrical lens. Any linesseen through the lens that are near to parallel with the cylindricallenses axis are seen as black, while any lines at an angle to the axisare blurred to a grey colour. This is shown in FIG. 10B, where a line1010 indicates the axis of astigmatism.

[0147] The astigmatism test 514 is designed to work in an interactivefashion with a patient over the WWW 202. The test 514 was devised toobtain a basic measure of the astigmatism of each of the patient's eyes.A corresponding traditional test would normally be carried out in theoptometry clinic using a series of cylindrical lenses, The currentinteractive test 514 uses a black fan-shaped visual object 1000displayed on a white background as shown in FIG. 10A.

[0148] The patient uses the mouse pointer 1903 and mouse button to drawon the fan-shaped object 1000. The patient is instructed by the programto cover the left eye and to observe the centre of the fan-shaped object1000 with the right eye. If the surrounding lines are perceived to be ofequal blackness, then the patient is to hold down the left mouse buttonand draw a horizontal red line 1020 across the image as shown in FIG.10C. If some of the lines are perceived to be much blacker and/orthicker than the rest, then the patient is instructed to use the leftmouse button to draw a red line 1030 across the blacker lines as shownin FIG. 10D. When satisfied with the line placement, the patient clickson a displayed Record button icon using the mouse 1903, and the angularspread defined by the red lines 1020,1030 is calculated. The inverse ofthe angular spread in degrees is used to calculate the percentage ofastigmatism. Typical levels are: mild (less than 30%), medium (30 to60%), and significant (greater than 60%). Thus, the narrower the spread,the greater the astigmatism.

[0149] The test is repeated with the left eye open and the right eyecovered.

[0150] Alternative Astigmatism Test (514)

[0151] In another embodiment of the first astigmatism test (514), thepatient is faced with a series of 18 randomised virtual box images 1040as shown in FIG. 10E. Each of the virtual boxes 1040 is made up of thinlines at orientations ranging from 0 to 170 degrees from the vertical.The patient is asked to cover one eye and look at the virtual box images1040 and decide which ones are darker or blacker than the rest. Thepatient is asked to then point at each dark virtual box with the mousepointer 1044 and click the left button of the mouse 1903. This will showa border around the vital box indicating that it has been selected Ifunsatisfied with any selection, the patient may click on it again tode-select it. When the patient has finished selecting the virtual boxes1040 that are perceived to be darker, the patient is advised to pressthe record button icon 1042 with the mouse pointer 1044. The angularspread as indicated by the angles of the lines making up the virtualboxes chosen is calculated.

[0152] The inverse of the angular spread in degrees is used to calculatethe percentage of astigmatism Typical levels are: mild (less than 30%),medium (30 to 60%), and significant (greater than 60%). Thus, thenarrower the spread, the greater the astigmatism

[0153] The test is repeated with the left eye open and the right eyecovered.

[0154] Results of Preliminary Tests

[0155] The results 516 of the preliminary visual acuity test 512 andastigmatism 1 test 514 are displayed in a graphical form as shown inFIG. 6. Based upon these two tests the patient is advised whether or notto seek further help, or alternatively, that their eyes are within thenormal range.

[0156] Static Tests 316

[0157] The static tests 316 are a series of tests designed to examine,in detail, several aspects of the patient's vision, includingmeasurements of the spherical and cylindrical abnormalities of theoptical system of each eye, and to also screen-for some eye diseases.

[0158] An examination for cataract, macula degeneration, and glaucoma isconducted through the prefilter contrast test 517, the patient historyquestions 518, the macula integrity test 534 and the peripheral visionsensitivity test 536 which are carried out in adult patients. Forchildren, many of the tests are similar to the adult tests but areadjusted for age differences in the responses. An additional set oftests including a saccades test 528 and a series of performance tests530 using objects 1500, 1510 and 1520 shown in FIGS. 15A to 15C is usedto test the child's visual skills relating to reading abilities.

[0159] In contrast to the preliminary screening tests 314, the patientdoes not see the results of the static test set 316. The patient isadvised that the results of the individual tests will be encrypted andsent to the central optometric laboratory for examination and analysisby a legally registered optometrist.

[0160] The individual parts of the static test set 316 have beendesigned to work together. The patient first carries out threequalitative tests which are used to give a broad understanding of thepatient's visual status and to determine which are the best quantitativetests to run to obtain optimal results. The first of the three is theprefilter contrast test 517 to give an indication of possible pathologyproblems and also large refractive abnormalities. This is followed bythe patient history question set 518 where information about thepatient's age, medical condition and vision problems is collected andscored and finally a discrimination test 519 which uses a largestationary boxed C object 1100 shown in FIG. 11 to estimate a grossvisual acuity.

[0161] Using information from the first three qualitative tests, andsubsequent quantitative tests, the program uses internal logic to enableit to adjust the tests used to obtain measurements that will give theoptimal results for each patient. The program follows one of severalcourses of action depending upon whether the patient was a child or anadult, whether there was a large or small refractive error and whetherthere was pathology indicated.

[0162] For example, a near normal patient might be given the distanceacuity C-test 520, the contrast pattern tests 525 and the astigmatismtest 526 or 527. A child patient with reading difficulties might also begiven the same tests adjusted for their age and in addition the saccadestest 528 and the child performance test 530. Alternatively, an adultwith a large refractive error and pathology indicated might have thetest distance of the distance acuity C-test 520 and the contrast test525 altered from 300 cm to 100 cm and be given the peripheral field test536 and macula integrity test 534.

[0163] In the static tests 316, the visual acuity is measured, using agrowing boxed C object 1100, but when indicated, with red and greencoloured backgrounds. The use of the coloured backgrounds in associationwith the white background, allows the spherical component to beaccurately estimated under some conditions.

[0164] The visual acuity is also measured, along with some signs ofpathology using the contrast pattern tests 525 which use colouredcontrast patterns. The combination of the results from the distanceacuity C-tests 520, 522, 524 and contrast tests 525 allow an accurateestimation of both spherical and cylindrical lens components.

[0165] The astigmatism 1 test 514 in the preliminary test section 312gave a qualitative estimation of the angle of the axis and a qualitativeestimate of the degree of the problems associated with the non-lenscomponents of the optical system.

[0166] In the static test section 316, the second astigmatism test 526is measured using a new visual object 1210, as seen in FIG. 12B. Thisgives an accurate measurement of both the angle of the axis and thecylindrical lens power needed to correct any problems due to theastigmatism. An alternative, third astigmatism test 527 using visualobjects 1225 or 1255 shown in FIGS. 12C, 12D and 12E may also be used toobtain an accurate measurement of the angle of the astigmatic axis. Theastigmatism tests 526 and 527 may be used separately or together asrequired.

[0167] The peripheral visual field test 536 is used to examine thesensitivity of the retinal photoreceptors to both white and colouredlight. Reductions in sensitivity in various regions of the retina areindicative of several pathological conditions including glaucoma, maculadegeneration, diabetic retinopathy, retinopathy, optic nerve headdiseases and neurological disorders such as stroke, cranial tumours,etc.

[0168] In adults, a macula degeneration test 534 is used to identifysigns of deterioration of the macula, whilst in children a saccades test528 is used to detect accuracy of performance of visual objectrefixation.

[0169] Prefilter Contrast Pattern Test 517

[0170] The test 517 was devised to obtain a qualitative assessment ofthe presence or absence of neurological or pathological conditions andgross refractive abnormality. The test uses an object 1265 shown in FIG.12F and an object 1270 shown in FIG. 12G. The objects 1265,1270 are each8 cm square-shaped grey-scale sinusoidal contrast test patterns on a midgrey background. The lines in the objects 1265 and 1270 are displayed inboth horizontally and vertically and when viewed from 300 cm will haveangular frequencies of three and six cycles per angular degree. Thehorizontal pattern 1265 has an angular frequency of 3 cycles per visualangular degree and the vertical pattern 1270 is shown with an angularfrequency of 6 cycles per visual angular degree.

[0171] The patient is given instructions on the video display 1914and/or programmed voice instructions as to how to run the test 517, andhow to set up the viewing distances. It is recommended that the test 517be carried out by two people, the patient and an assistant. It is alsopossible for a single person to perform the test, but with a little moredifficulty.

[0172] The test 517 involves the assistant starting the test running byselecting a Start button icon using the mouse 1903, and the patient,with one eye covered, watching the contrast patterns 1265 and 1270whilst sitting at a distance of 300 cm, and directly facing the screendisplay.

[0173] The test 517 starts by displaying the contrast patterns 1265 and1270 at a very low contrast (the amplitude of the sinusoidal variationin contrast is approximately 3% of full range) and the contrast isincreased by the assistant selecting an icon on the display 1914 usingthe mouse 1903 until the patient can see the direction of the lines inthe contrast patterns 1265 and 1270. At this stage the assistant pressesa button on the screen display 1914 using the mouse pointer 1903 torecord the result. The test is repeated with the other eye.

[0174] Normal results are indicated if the patient can see the contrastpatterns at very low contrast. Medium contrast levels indicate largerefractive error in the optical system and mild pathology problems. Highcontrast levels indicate very large refractive problems, variouspathologies and neurological problems.

[0175] Patient History Questions 518

[0176] A series of questions are presented in multiple choice format onthe patient's vision-related medical background and their behaviourunder various environmental situations and using symptomatic analysis todetermine whether any vision related problems are present. For example,patients are asked whether they can easily read the time on theirwatches or the fine print on the labels on a food container. Points areallocated depending on the patient's response. The allocated points areused as an indication of certain visual problems. The set of questionsis designed to seek out common optometry problems and pathology. Theresults are scored and used along with the prefilter contrast patterntest 517 to indicate the best course of action for further tests.

[0177] To do the test 518, the patient may either sit in front of thecomputer and tick relevant check boxes on the video display 1914 usingthe mouse pointer 1903 after reading the multiple choice questionthemselves. Alternatively the assistant may read the questions aloud andtick the patient's reply.

[0178] Visual Acuity Discrimination Test 519

[0179] This test 519 was devised to examine for high spherical and/orcylindrical refractive error in patients. The information gained fromthe test 519, together with the information from the prefilter contrasttest 517 and the patient's history 518, is used in deciding which arethe most appropriate following tests to run to give the optimal results.

[0180] The test 519 uses a 9 cm wide black boxed C object 1100 on awhite background which is placed stationary in the centre of the videodisplay screen, as shown in FIG. 11. The gap in the boxed C object maybe facing in any direction. The size of the object may vary from time totime to suit local conditions.

[0181] The patient is given instructions on the video display 1914and/or programmed voice instructions as to how to run the test, and howto set up the viewing distances. It is recommended that the test 519 becarried out by two people, the patient and an assistant. It is alsopossible for a single person to perform the test, but with a little moredifficulty.

[0182] The test 519 involves the assistant staring the test running byselecting a Start button icon using the mouse 1903, and the patient,with one eye covered, viewing the boxed C object 1100 whilst sitting ata distance of 300 cm, and directly facing the screen display. Thepatient is asked to tell the assistant whether they can clearly see thegap in the boxed C object 1100 and which direction the gap is facing.Their answer is recorded as being able to see or not see the gap and itsdirection. The test is repeated for the other eye.

[0183] White Visual Acuity Test 520

[0184] The test 520 was devised to obtain an accurate measurement of thevisual acuity of the patient's eyes. A corresponding traditional testwould normally be carried out in the optometry clinic by examining fixedpredetermined letter sizes on a standard letter chart.

[0185] The test 520 uses, also from FIG. 11, four black visual objects1100 randomly displayed on a white background, each one similar to thealphabet letter C, but rotated such that the gap is facing up, down,left and right respectively. Each object 1100 is referred to as a boxedC object. The test 520 uses a partial border or box area around the Cobject to elicit the visual phenomenon known as crowding, in whichletters are more difficult to identify if close to each other.

[0186] An alternative version of the test 520 uses the capital letter Ein place of the letter C. The objects used would then be called boxed Eobjects.

[0187] The patient is given instructions on the video display 1914and/or programmed voice instructions as to how to run the test, and howto set up the viewing distances. It is recommended that the test 520 becarried out by two people, the patient and an assistant. It is alsopossible for a single person to perform the test 520, but with a littlemore difficulty.

[0188] The test 520 involves the assistant starting the test running byselecting a Start button icon using the mouse 1903, and the patientwatching the boxed C object 1100 grow from a small size to a very largesize on the screen The boxed C object 1100 size ranges from 2 to 150 mmin steps of 2 mm. When the patient can see the direction of the gap inthe letter C, the patient asks the assistant to stop the growth of theboxed C object 1100 by clicking the mouse 1903 over the direction arrowicon, such as the icon 920 seen in FIG. 9.

[0189] Two controls are available to adjust the speed of the test 520.One controls the time delay interval between selecting the Start buttonand the start of the display of the an assistant, as it allows thepatient time to get into the test position. The time delay interval canbe set in the range between 0.5 and 20 seconds.

[0190] The second speed control allows adjustment of the object growthspeed which is a time interval between display of successive largerboxed C objects 1100. This is useful if the patient has poor vision asit increases the size of the boxed C objects 1100 more rapidly. Theobject growth speed can be varied between 0.5 and 5 seconds.

[0191] The test 520 is performed at two or three distances from thedisplay screen 1914 depending upon the size of the refractive error, thedistances being 40 cm, 100 cm and/or 300 cm. At each distance, the test520 is run for the left eye and the right eye individually. Each run ofthe test 520 is repeated four times to obtain an average object size atwhich the direction button icon 920 was selected. This gives an idea asto visual function for close up tasks and for more distant tasks.

[0192] Red Visual Acuity Test 522

[0193] The test 522 has been devised to obtain a more accuratemeasurement of the visual acuity and refractive status of the patient'seyes, when carried out in association with the white and green visualacuity tests 520,524. Visual acuity is normally carried out in theoptometry clinic by examining black letter sizes on a standard whitebackground letter chart. The test uses the same four black visualobjects 1100 used in the white visual acuity test 520, but in thepresent test 522 they are displayed on a red background (RGB=255, 0, 0).Once again the use of a partial border or box area around the C objectelicits the visual phenomenon known as crowding where letters are moredifficult to identify if close to others. The letter E may be used inplace of the letter C.

[0194] The test procedure is the same as for the boxed C test in thewhite visual acuity test 520. The patient is given instructions on thescreen and/or programmed voice instructions as to how to run the test522 and how to set up the viewing distances. It is recommended to thepatient that the test 522 is carried out by two people, the patient andan assistant, although it is possible for a single person to run thetest 522.

[0195] The test 522 involves the assistant starting the test running byselecting the Start button and the patient watching the boxed C object1100 grow from a small size to a very large size on the video display1914. The object 1100 ranges in size from 2 to 50 mm in steps of 2 mm.When the patient can see the direction of the gap in the letter C thepatient asks the assistant to stop the growth of the boxed C object 1100by selecting the direction arrow button 920 using the mouse 1903. Asbefore two controls are available to adjust the speed of the test. Thefirst controls the time delay interval between selecting the Startbutton and the start of the display of the boxed C object 1100. This isrequired if the patient conducts the test unassisted.

[0196] The second speed control allows adjustment of the object growthspeed, which is a time interval between the display of successive,larger boxed C objects 1100. This is useful if the patient has poorvision, as it increases the rate at which the boxed C object 1100 growsto a large size, thus reducing the waiting period.

[0197] The test 522 is performed at two or three distances from thescreen depending upon the size of the refractive error, 40 cm, 100 cmand/or 300 cm. At each distance the test 522 is run for the left eye andthe right eye individually. Each run of the test 522 is repeated fourtimes to get an average object size at which the stop button wasselected. The size of the boxed C object 1100 viewed from a knowndistance is related to the visual acuity with corrections for redcoloured light. Using different background colours tests differentcomponents of the visual process. In particular a red background is usedin identifying long sightedness.

[0198] Green Visual Acuity Test 524

[0199] The test 524 is carried out in conjunction with the white and redvisual acuity tests 520,522 in order to obtain a more accurate measureof the visual acuity and refractive status of the patient's eyes. Visualacuity is normally carried out in the optometry clinic by examiningblack letter sizes on a standard white background letter chart. The testuses the same four black visual objects 1100, the boxed C objects, thatwere used in the white and red visual acuity tests 520,522. In this casethe boxed C objects 1100 (RGB=0,0,0) are displayed on a green backgroundRGB=0, 210, 0). As described before, the partial border around the Cobject elicits the visual phenomenon known as crowding. The letter B maybe used in place of the letter C.

[0200] The test procedure is the same as was used in the white and redvisual acuity tests 520, 522. As before it is recommended that the test524 is carried out by two people, the patient and an assistant, althoughthe patient may run the test 524 alone using the time delay intervalcontroller and the object growth speed controller. The results of thetest relate to visual acuity with corrections for green-coloured light.The green background helps in the identification of short sightedness.

[0201] Contrast Pattern Test 525

[0202] The test 525 was devised to give an accurate measure of visualacuity and an indication of certain underlying pathology conditions.

[0203] The test uses objects 1275, 1280 and 1285 shown in FIGS. 12H and12J. The objects 1275, 1280 and 1285 are sinusoidally varied contrasttest patterns displayed in 8 cm squares. Object 1275 is a grey-scalepattern with a vertical pattern of 36 cycles per visual angle whenviewed from 300 cm, object 1280 is a red-scale vertical pattern of 24cycles per visual angle and object 1285 is an example of a blue-scalepattern showing horizontal lines at 12 visual cycles per visual angulardegree. The patterns in objects 1275, 1280 and 1285 may be renderedobscure by poor reproduction of darkly shaded images.

[0204] The lines in the patterns 1275,1280 and 1285 are typicallydisplayed in both horizontal and vertical orientations, but may be alsodisplayed at other angles, and when viewed from 100 cm or 300 cm willhave angular frequencies from three to thirty six cycles per angulardegree. The amplitude of the sinusoidal variation in contrast is set to50% of full range.

[0205] The patient is given instructions on the video display 1914and/or programmed voice instructions as to how to run the test, and howto set up the viewing distances. It is recommended that the test 525 becarried out by two people, the patient and an assistant It is alsopossible for a single person to perform the test, but with a little moredifficulty.

[0206] The test 525 involves the assistant starting the test running byselecting a Start button icon using the mouse 1903, and the patient withone eye covered watching the contrast patterns 1275, 1280, 1285 whilstsitting at a distance of 100 cm or 300 cm, and directly facing thescreen display.

[0207] The contrast patterns 1275, 1280, 1285 having the highestfrequency, 36 cycles per degree, are displayed first and then patternswith decreasing frequency are displayed until the patient can see thedirection of the lines in the test pattern. At this stage the assistantselects a button on the screen display 1914 using the mouse pointer 1903to record the result. The tests are performed for grey, red and bluecontrast patterns. The test is repeated for the other eye.

[0208] The pattern of results for the grey, red and blue contrastpatterns when measured at 100 cm or 300 cm or both can be related toboth the magnitude of the spherical and cylindrical refractivecomponents of a corrective spectacle prescription.

[0209] Contrast C Test 532

[0210] One of the problems with optometric tests is that they may giveincorrect answers when the patient is suffering from some visualdisorder. Several disorders including astigmatism, cataracts, maculadegeneration and pituitary tumours may cause a reduction of sensitivityto visual images.

[0211] A contrast test 532 is provided, which in cross reference withthe other tests, indicates potential problems resulting from thesedisorders.

[0212] The test 532 uses a very light grey growing boxed C object(RGB=240, 240, 240) on a white background (RGB=255, 255, 255). Thisboxed C object has a very low contrast to the white background but hasthe same shape as the objects 1100 discussed earlier. The boxed-C objectnormally detects mild to severe astigmatism, and will give an indicationof problems associated with several disorders depending on the severityof the disorder. The procedure of the test 532 is identical to that ofthe white, red and green visual acuity tests 520,522,524. The results ofthis contrast test 532 are used in conjunction with the white, red andgreen acuity tests 520,522,524. A poor result in the contrast test 532indicates the possible presence of visual disorders, and the patient isadvised to seek further examination from an optometrist orophthalmologist.

[0213] Second Astigmatism Test (Virtual Box Astigmatism Test) 526

[0214] The preliminary tests 314 provided to the patient included afirst astigmatism test 514, and a brief description of the condition wasprovided in the discussion of the first astigmatic test 514.

[0215] The second astigmatism test 526 forms part of the static testing316, and makes use of a contrast graded arrowhead shaped visual object1200 which is displayed on a white background as shown in FIG. 12A. Thearrowhead object 1200 is rotated through 180° during the test 526, inintervals of 1°.

[0216] The test 526 uses a virtual box image 1210 composed of twounbound box forms one smaller, the inner vial box, located inside alarger virtual box. Each virtual box is made up of short parallel linesoriented by the user. The lines inside the smaller inner virtual box areperpendicular in orientation to those in the outer virtual box.

[0217] The test program allows the patient to accurately determine theangle of the astigmatic axis by the differential grey shading of thesides of the arrowhead object. A slider bar is provided on the videodisplay 1914, and the arrowhead object 1200 can be rotated by using themouse 1903 to move the slider bar. The patient is instructed to rotatethe arrowhead object 1200 until both its sides are perceived to be ofequal blackness. The patient then selects a Record icon to store theaxis of astigmatism, which is determined by the arrow direction. Theaxis will be different for each eye, and if the patient does not havemuch astigmatism, the arrowhead object 1200 will look substantially thesame at all angles.

[0218] The next part of the test 526 carries out a measurement of theastigmatic power range, which is determined by the difference betweenthe near focal range and the far focal range. The virtual boxes 1210shown in FIG. 12B are displayed on the video display 1914 with the lineorientation of the inner virtual box in the same orientation asdetermined by the arrowhead object 1200 in the first part of test 526.The patient is instructed to state whether the inner smaller virtual boxappears to stand out from the larger virtual outer box or the outervirtual box appears to stand out from the inner smaller box. The patientis asked to move towards or away from the video display 1914 until thetwo sets of virtual boxes appear to have equal blackness, darkness orthickness. It is then necessary to measure the distance from the eye tothe video display 1914.

[0219] The result is typed into a box on the video display 1914 and theRecord icon is selected using the mouse 1903 to store the information.

[0220] The patient is then instructed to move towards or away from thevideo display 1914 until the inner smaller virtual box of the object1210 appears to be blacker, darker or thicker than the outer largervirtual box of the object 1210. Once again the distance from eye tovideo display 1914 is measured, and the result is entered into a box onthe video display 1914 and the Record button is selected.

[0221] As the final step of this test 526, the patient is instructed tomove towards or away from the video display 1914 until the larger outervirtual box of the object 1210 appears to be blacker, darker or thickerthan the inner smaller virtual box of the object 1210. As before thedistance between the eye and the video display 1914 is measured, and theresult is entered into a box on the video display 1914 and the Recordbutton is selected using the mouse 1903. The lines on the virtual boxescan also be substituted with coloured lines and the test repeated in thesame manner.

[0222] The astigmatic power is determined by the difference between thenear focal range and the far focal range. These latter ranges arecalculated using the distance measurements taken during the test 526.

[0223] The Third Astigmatism Test (Windmill Test) 527

[0224] In the second astigmatism test using the virtual box test 526,the axis of astigmatism is found using a rotating arrowhead. Thewindmill test 527 provides an alternative test that under someconditions proves to be more sensitive and more readily acceptable tomany patients.

[0225] The windmill test 527 uses an object 1220 shown in FIG. 12Ccomposed of a series of lines (eg 1225, 1226) having a thickness whichmay be varied. Lines 1225, 1226 are radially distributed as an annulusaround a centre region containing a V shaped arrowhead object 1230,which is also shown in FIG. 12D and which can be rotated through 360degrees. When the test is running, the radial lines 1225, 1226 arerotated clockwise around the centre like the vanes of a windmill. Thespeed of rotation is adjustable from 1 to 20 angular degrees per secondand the thickness of the lines 1225, 1226 is adjustable from 1 pixel to20 pixels.

[0226] The rotation of the radial lines 1225, 1226 draws the attentionof the viewer with astigmatism to the fact that those of the lines 1225,1226 lying in the axis of astigmatism are seen to be darker than others.The V shaped arrow 1230 can then be rotated to point to the centre ofthe axis of astigmatism. When near the centre of the axis, the equaldarkness of the two sides of the V shaped arrowhead 1230 can be used forfine tuning in a similar manner as with the arrowhead object 1200 usedin the second astigmatism test 526.

[0227] The ability to vary the thickness of the lines 1225, 1226 duringrotation of the radial lines helps patients with various degrees ofastigmatism to adjust the line thickness to an optimal thickness fortheir individual vision problem.

[0228] When the patient has considerable blur owing to a large sphericalrefractive problem in addition to the astigmatism, the radial lineobject 1220 shown in FIG. 12C becomes less effective. Under theseconditions an alternative hexagonal object 1250, shown in FIG. 12E, maybe used instead of the radial line object 1220. The object 1250 consistsof an outer hexagonal shape 1255. From each vertex of the hexagon 1255,a line 1257 projects towards the centre of the hexagon 1255. The lines1257 do not reach the centre of the hexagon 1255 but leave a centralclear region. A line 1260 is positioned in the clear central region andmay be moved independently of the hexagon object 1255. The central line1260 is used with the hexagonal FIG. 1255 to align to the angle ofastigmatism.

[0229] When the test is running the hexagonal part 1255 of object 1250shown in FIG. 12E is rotated clockwise around the centre. The speed ofrotation is adjustable from 1 to 20 angular degrees per second and thethickness of the lines 1257 is adjustable from 1 pixel to 20 pixels.

[0230] The rotation of the hexagonal object 1250 draws the attention ofthe patient with astigmatism to the fact that the divisions and sides ofthe hexagon 1250 lying on the axis of astigmatism are darker than theremaining divisions and sides. The central line 1260 shown in the object1250 can then be rotated to align with the hexagonal dividing lines 1257that appear darkest and match the axis of astigmatism which is parallelto the angle of the darkest sides. When nearing the alignment to thedarkest of the dividing lines the central line 1260 will appearcontinuous and bolder.

[0231] The patient is given instructions on the video display 1914and/or programmed voice instructions as to how to run the test, and howto set up the viewing distances. It is recommended that the test 527 becarried out by two people, the patient and an assistant. It is alsopossible for a single person to perform the test, but with a little moredifficulty.

[0232] The test 527 involves the assistant starting the test running byselecting a Start button icon using the mouse 1903, and the patient withone eye covered watching the rotating radial line FIG. 1220 or hexagonalFIG. 1250 whilst sitting at a distance of 100 cm, and directly facingthe screen display.

[0233] The end point of the test 527 is recorded by the assistantselecting a record button using the mouse pointer 1903 when thearrowhead object 1230 of the radial line object 1220 or the centre line1260 of the hexagon object 1250 is indicating the axis of astigmatism.The test 527 is repeated for the other eye.

[0234] Near Visual Acuity Test 529

[0235] The test 529 was devised to give an accurate measure of visualacuity at near distances. The test uses a small box shaped window 1290shown in FIG. 12K in which is displayed a series of six to eightrandomly generated numerals 1292. In the example shown in FIG. 12H therandom number 1292 is “524869”. The numerals 1292 start off at thebeginning of the test at the screen resolution which is approximately 5point on a screen operating at a resolution of 800×600 pixels, but maybe smaller on higher resolution screens. The numerals 1292 increase insize by whole points at the selection of an arrow 1294 activated by themouse pointer 1903. The object of the test 529 is to measure thesmallest point size of the numerals 1292 that the patient can see. Thenumerals 1292 are generated randomly so that the patient cannot guessthem. The point size of the numerals 1292 is used to determine anestimate of the near visual acuity.

[0236] The patient is given instructions on the video display 1914and/or programmed voice inductions as to how to run the test, and how toset up the viewing distances. It is recommended that the test 529 becarried out by two people, the patient and an assistant. It is alsopossible for a single person to perform the test, but with a little moredifficulty.

[0237] The test 529 involves the assistant starting the test running byselecting a Start button icon using the mouse 1903, and the patient withone eye covered watching the number box 1290 whilst sitting at adistance of 40 cm, and directly facing the screen display.

[0238] The end point of the test is reached when the patient can readaloud the sequence of numerals 1292 displayed on the screen withouterror. This point is recorded by the assistant selecting a record buttonusing the mouse pointer 1903.

[0239] The test 529 is repeated with the other eye.

[0240] First Peripheral Field Test 536

[0241] A number of pathological disorders are known to cause a reductionof sensitivity or loss of photoreceptive function in the retina of theeye. The peripheral field test 536 is designed to map the sensitivity ofthe photo receptors.

[0242] If the patient normally wears visual aids such as spectacles orcontact lenses they should be used during the test.

[0243] The test 536 as seen in FIG. 13 presents spots 1330 which arelight grey to white in colour on a mid-grey background screen 1310 for ashort interval of time. The patient tracks a moving target object 1320on the video display 1914 using the mouse pointer icon 1350, and when aspot 1300 appears the patient is instructed to press a button on themouse 1903 to record the sighting.

[0244] When a spot 1300 is sighted the position of the spot 1300 isrecorded, allowing a map of photoreceptor sensitivity to be drawn. Lossof sensitivity in various regions of the retina is indicative ofdifferent types of visual disorder.

[0245] A typical screen used in the peripheral field test 536 is shownin FIG. 13. The patient is instructed to cover his or her left eye witha patch, and then to move his or her face to a position 25 cm from thevideo display 1914. In order to support the patient's head and helpmaintain it at the correct distance and height from the video display1914, the patient is instructed to rest his or her elbow on a table andto rest his or her chin in the left hand.

[0246] The patient is then instructed to fixate on the central “orangecircle” target object 1320. While fixating on this target object 1320,the patient is to adjust his or her distance from the video display 1914by rocking backwards or forwards on his or her elbow until the blackoval 1330 on the right side disappears into the eye's blind spot. Thepatient's eyes should also be at the same height as the orange circletarget object 1320.

[0247] The patient then moves the mouse pointer icon 1350 into themiddle of the target object 1320 using the mouse 1903. A soon as thearrow 1350 is in the correct position overlapping the target object1320, the mouse pointer icon 1350 will change into a multidirectionalicon 1360. The goal is then to keep the multidirectional arrow 1360steady inside the target object 1320 at all times as the target object1320 moves around on the video display 1914. Test results are onlyrecorded while the multidirectional arrow 1360 is maintained inside thetarget object 1320. Intermittently, while the patient is moving themultidirectional arrow 1360 inside the moving target object, a grey spotwill flash somewhere in the patient's peripheral vision. Each time aspot 1300 is perceived in peripheral vision, the patient clicks on theleft mouse button. This process is repeated each time a spot 1300 isseen flashing somewhere on the video display 1914. Each time the patientcurrently observes a spot 1300, a smiley-face object 1340 is displayedon the video monitor 1914.

[0248] The procedure is then repeated for the left eye.

[0249] To increase the field size for the test a new fixation point isselected at each corner and the test repeated. Each time the head isrepositioned to match being directly in front (height and in line) ofthe fixation spot.

[0250] Macula Integrity Test 534

[0251] The purpose of this test is to determine the integrity of themacula and to record if any changes or deteriorations are occurring. Thetest 534 makes use of a pattern of white lines 1410 arranged in a squaregrid on a black background 1400 as shown in FIG. 14. A red fixation spot1420 is drawn in the centre of the grid 1410. A white oval object 1430,flickering at a rate of 3 Hz, is positioned to either or the right orleft side of the grid pattern depending on which eye is being tested.

[0252] If the patient normally wears visual aids such as spectacles orcontact lenses they should be used during the test.

[0253] The patient is instructed to look at this central red dot 1420during the test procedure. While fixating on this target object 1420,the patient is to adjust his or her distance from the video display 1914by rocking backwards or forwards on his or her elbow until the whiteflickering oval 1430 on the right side disappears into the eye's blindspot. The patient's eyes should also be at the same height as the reddot target object 1420.

[0254] By repeatedly drawing the focus of attention to the centre of thegrid pattern 1410, a more stable mapping of any irregularities may beachieved.

[0255] The test 534 is standardised by making use of the patient's blindspot. The vertical oval 1430 is located to the right of the grid pattern1410 when testing the right eye, and the similar vertical oval 1430 ispositioned to the left of the grid pattern 1410 when the left eye isbeing tested. The size of this vertical oval 1430 is set to be slightlysmaller than the blind spot at a working distance of between 25 and 30cm from the video display 1914. The patient is instructed to cover hisor her left eye, and then, while focusing attention on the central reddot 1420, to move his or her head towards or away from the video display1914 until the white vertical oval 1430 on the right side of the grid1410 disappears into the blind spot. This should occur when the eye isabout 25 to 30 cm from the video display 1914. Once this positioning isachieved, the patient is instructed to note any fading out of the linesor squares in the grid 1410; any distortions of the lines or squares inthe grid 1410, and any gaps or incomplete lines or squares. The mouse1903 is then used to click over the area where any observed distortionsappear.

[0256] The procedure is then repeated with the right eye covered.

[0257] If any distortions of the grid 1410 have been noticed, thepatient is requested to contact a local eye care practitionerimmediately.

[0258] A graphical map is recorded showing any noted distortions. Thesize and location of the noted distortions provide an indication of theseverity of any changes which have occurred to the macula.

[0259] Saccades Test 528

[0260] Three visual performance tests are provided in order to evaluatea child's ability to fixate, refixate and visually scan characterspresented on a flat video display 1914. Each of the three tests examinesa different scanning function used in gathering information during thereading process. The tests 528 need to be carried out with theassistance of a supervising adult. In each case the child is given a settask, and the program will then record the time taken to complete thetask, and the numbers of errors made. The child's results arecross-correlated with tabulated data relating to expected performanceversus age. The result of this operation gives an indication as to howthe child's vision may be affecting his or her academic performance.

[0261] The first test checks the accuracy with which a child can adjustfixation from a first point to a second point which has a randomseparation, but following the conventional sequence used in westernscripts in which text flows from left to right and top to bottom.

[0262] A block of numbers 1500 is presented in the middle of the videodisplay 1914 with an irregular spacing between the numbers, as shown inthe example of FIG. 15A. The object of the test is for the child to readall the numbers in the block 1500 as quickly fingers to search and findnumbers. A series of 50 numbers is presented. The supervising adultselects a Start and Stop button using the mouse 1903 and notes thenumbers of errors made by the child.

[0263] The second saccades test looks at the child's ability to scan andidentify an image, retain it in memory, and simultaneously count objectsand add them to a mental tally.

[0264] A block of numbers 1510 is presented in the middle of the videodisplay 1914 consisting of a matrix with ten rows and seven columns, asseen in FIG. 15B. The child is instructed to count how many instances ofa particular number are present in the entire block of numbers 1510.

[0265] The supervising adult will again select Start and Stop buttonicons to record the beginning and end of the test, and will record thetally counted by the child. The test is presented four times with fourdifferent number searches. For example the child could be asked to counthow many times the number “five” appears in the block of numbers 1510 onthe video display 1914.

[0266] The time taken to complete the test is recorded and also howsuccessful the child was at identifying all the numbers present in theblock of numbers 1510.

[0267] The third saccades test is a visual-verbal task which tests thechild's peripheral visual location and verbal identification skills. Thenumbers 1 to 20 are displayed on the video display 1914 in a randomsequence determined by the computer program. Next to each of thedisplayed numbers, a randomly chosen letter from the alphabet isdisplayed. An example of this viewing object 1520 is shown in FIG. 15C.During the test, the child has to locate each number sequentiallystarting with 1. As the number is located, the child has to call out thenumber and the associated letter. The supervising adult selects a Startbutton to begin the test and a Stop button once it is ended. The adultalso needs to record the child's performance in the test, with respectto whether the numbers were located in the correct sequence, and whetherany letters or numbers were misread. The child has to perform this taskusing the eyes only, without pointing with his or her fingers to helpidentify the characters. The helper is also asked to identify whetherthere was a lot of head movement during the performance of the test.

[0268] At the end of the three tests 528, the program provides a reportshowing the levels achieved by the child in each test and how they ratecompared with tabulated age-related data. If a child fails to reach anadequate level for his or her age, the program will display a message onthe video display 1914 to the effect that the child's vision may beaffecting academic performance and recommending that the child is givenvision therapy to counteract the weaknesses.

[0269] Colour Vision Test 538

[0270] There are two purposes to testing colour vision. The first is todetermine if a patient has difficulty discriminating colours which couldaffect the patient's daily life. Examples of tasks where colourdiscrimination is required are the identification of electroniccomponents, and the identification of coloured signals by pilots, traindrivers etc. The second purpose of testing colour vision is to identifydeficiencies which are due to disease such as glaucoma or diseases ofthe optic nerve.

[0271] The actual test implemented can be a pre-tested and standardisedcolour vision test used with the permission of the copyright owner. Thepre-tested and standardised colour vision test is adapted to run as atest 538 on the flat video display 1914, and to provide an automaticrecording system in order that untrained users can carry out the test538. The results are recorded in a computer memory, and areautomatically analysed, calibrated and scaled by the computer software

[0272] Dynamic Tests 318

[0273] The following series of tests is designed to assess the binocularstatus of the patient. In other words the purpose is to determine thatthe two eyes are working together. The tests assess whether the patienthas an accurate binocular fixation (no eye muscle imbalances and/orsuppression). They also test the patient's fusion skills and depthperception.

[0274] In order to run these tests it is necessary to present a distinctimage to either eye. This is achieved by using goggles which havedifferent coloured filters for either eye, or alternatively have liquidcrystal display (LCD) filters which are polarised differently for eacheye. When different coloured filters are used, one lens will be red andthe other will be green or blue. It is necessary that the patient obtaina suitable pair of goggles before the test can be done. The colouredfilter goggles can be obtained from AiVision Pty Ltd, Sydney, Australia(www.aivision.com.au) over the World Wide Web 202.

[0275] Binocular Vision Test Suppression Test 540

[0276] In the test 540, six objects (three paired sizes) are displayedon the video display 1914 simultaneously. The objects are coloured insuch a way that a patient wearing the goggles described above would onlysee three objects with either eye. Thus, if one eye were to be covered,the user would only see three objects. If the other eye were covered,the other three objects would be seen. The purpose of the test is toview the video display 1914 with both eyes open and to note how manyobjects can be seen simultaneously and the degree of suppression.

[0277] The patient is asked using the mouse to click over each of theshapes that they see on the video monitor. The results are automaticallyrecorded, analysed and calibrated by the program on the computer.

[0278] If only three or two similar shaped objects are seen then thepatient is only using one eye and thus cannot appreciate truethree-dimensional vision. If a combination of the shapes are seen itdenotes there is some level of simultaneous binocular vision present Ifthe smaller central images are left out it denotes small centralsuppression or a fine binocular imbalance.

[0279] The test 540 is conducted with the eyes positioned 40 cm from thevideo display 1914 while wearing the red and green/blue goggles (withthe red filters in front of the left eye).

[0280] If the patient reports an incorrect response, in which only threeor two similar shaped objects are seen, then no further dynamic testingis performed. A message will be displayed on the video display 1914advising the patient to consult the nearest practitioner.

[0281] Binocular Vision Test 2: Phoria 542

[0282] The purpose of the phoria test 542 is to determine how well thetwo eyes are aligned. The test 542 presents five red square objects1610, four of which are positioned at the corners of the screen 1600while the fifth square 1610 is positioned at the centre as seen in FIG.16. While the patient is wearing the coloured goggles, these red squareobjects 1610 will only be visible to one eye. A green cross-shapedobject 1620 is also displayed, which is only visible to the other eye.

[0283] The patient is instructed to position his or her head 40 cm fromthe video display 1914 while wearing the coloured goggles. The object isthen to move the green cross-shaped object 1620 using the mouse 1903 andto position it inside each of the five red square objects 1610 in turnOnce the patient perceives the cross to be inside a square 1610, theleft mouse button is clicked to record the perceived position. Theprocedure is continued until the patient has attempted to position thegreen cross 1620 in each of the five red squares 1610.

[0284] The test 542 records the disparity between the true and theperceived positions of the two objects in each of the five locations.Any disparity between the real and perceived location of the two objectswill indicate a muscle imbalance, ie. whether the eyes under-converge,over-converge or have a vertical imbalance. Any mis-alignment is anindication of the ocular posturing of the eyes during the state of rest.

[0285] Binocular Vision Test 3: Fusion 544

[0286] The purpose of the fusion test 544 is to test the visual system'sability to fuse two images into a single image. The test 544 makes useof two rectangles 1700, 1710 of identical size as seen in FIG. 17. Thefirst rectangle 1700 has a speckled red background, and is only visibleto the eye associated with the red filter of the goggles. The secondrectangle 1710 has a green or blue speckled background, and is hencevisible only to the other eye.

[0287] At the start of the test the two rectangles 1700,1710 areoverlayed to appear as one image. A red and green/blue random dotstereogram of a circle 1720 is displayed on the video display 1914 suchthat it will appear within the overlayed rectangles 1700,1710 in one ofthree locations, namely to the left of the rectangle, in the middle, orto the right of the rectangle. By selecting one of three buttons1730,1740,1750 on the video display 1914 using the mouse 1903, thepatient is able to identify the location of the circle 1720 within therectangle.

[0288] In the first part of the test 544 the red-coloured rectangle 1700is moved to the right. Once again the patient is asked to identify thelocation of the circle 1720 within the perceived rectangle. This teststhe ability of the brain to hold the two images together. If thelocation is correctly identified, the red coloured rectangle 1700 ismoved further to the right. This process is repeated until the break ofconvergence fusion is reached. At this point the patient will not beable to identify where the circle 1720 is located in the rectangle.

[0289] In the second part of the test the procedure is the same exceptthat the red rectangle. 1700 is moved to the left from the overlappingstart position. The point at which the patient can no longer identifythe location of the circle 1720 within the perceived rectangleidentifies the divergence fusion demand.

[0290] The maximum separation in each direction relates to the fusion orrange for both divergence and convergence. The results are recorded andautomatically analysed, calibrated and scaled by the computer programstored in the computer 1901. The results are recorded in dioptric values(prism diopters disparity).

[0291] Binocular Vision Test No. 4: Stereopsis 546

[0292] This test 546 is similar to the fusion test 544, but instead ofmoving the background rectangle 1700, the stereoscopic informationdefining the circle 1720 is varied. The purpose of the test 546 is toclick on one of three boxes 1730, 1740, 1750 on the screen marked “L”“M” “R” respectively as seen in FIG. 18, in order to indicate whetherthe circle 1720 is perceived to be located to the left, in the middle orto the right of the background rectangle 1800. If a correct response isgiven the stereoscopic demand is increased until the patient is unableto tell where the circle 1720 is located within the background rectangle1800.

[0293] The test 546 is conducted with the eyes 40 cm from the videodisplay 1914 while wearing the red and green/blue goggles (the redfilter in front of the left eye).

[0294] A rectangle 1700,1710 with either a red or a green/blue speckledbackground is presented individually to each eye. A circular stereotarget 1720 is randomly superimposed in any one of three locationswithin the background rectangle 1800 as shown in FIG. 18.

[0295] The test 546 is repeated up to a further four times usingrectangles 1700, 1710 containing circles 1720 where the depth disparitybecomes more acute.

[0296] The results are automatically recorded, analysed and calibratedby the program on the computer 1901 in seconds of arc.

[0297] It will be appreciated from the above that the various visualtests, with the exception of the test setup (calibration), althoughdescribed in a certain order, need not be performed in any particularorder, or need all be performed, depending upon the type of examinationthat is desired. Typically however, the application program, onceenabled for patient testing, will take the patient through the varioustests in a step-by-step, test-by-test fashion until optical examinationis complete and a thorough evaluation of the test data can then beperformed.

[0298] Diagnostic Assistant Program

[0299] When the series of static and dynamic visual tests 316, 318 hasbeen completed, the patient responses representing the results of thetests 316, 318 are encrypted by the active document installed on thepatient's local computer 1901. The encrypted results are then sent backvia the World Wide Web 202 to the host computer system 214, where theresults are decrypted and analysed, ideally by a legally registeredoptometrist trained in the use of the program and tests, who is able toformulate and give professional advice on corrective lens prescriptionsor recommendations regarding further treatment. The recommendations maybe returned to the patient by e-mail 232 or by regular post.

[0300] In an alternative approach, the diagnosis may be performed by adiagnostic assistant program 700. This is a computer program which usesartificial intelligence technology including logic code and artificialneural networks in order to mirror the way a trained optometrist wouldanalyse the optometric data obtained from clinical testing of thepatient's visual functioning. In the first instance the clinicalvalidation 224 can screen the results of the remote testing in order toensure reliability and consistency of the test results. The diagnosticassistant program 700 can then calculate a suitable lens prescription inorder to correct the patient's refractive condition using an artificialintelligence/logic sequence described below. This analysis could bebased either on the results of the flat screen testing describedearlier, or alternatively could be based on standard clinical optometrictests. In the latter case the data from the tests would have to becaptured in a computer readable format.

[0301] The use of the diagnostic assistant program can speed up the lensprescription process considerably, and further provides a standardobjective reference in analysing visual functions.

[0302]FIG. 7 illustrates the data flow through the diagnostic assistantprogram 700 (named OptiVal) during the analysis relating to the opticallayer 100. The diagnostic assistant program 700 is composed of a largenumber of logical equations organised in modules which representdifferent parts of the visual analysis process. Each module interactswith other modules in order to provide an analytical chain which hasbeen adjusted experimentally to give suitable recommendations for lensprescriptions. The supervisory module 700 first considers the data 702relating to the static tests of the right eye, and data 704 relating tostatic data for the left eye. The analysis then proceeds to acuity data708 gathered during the tests 314, 316, 318 for either eye. Thereafterthe spherical data 710 is considered, followed by an analysis of theastigmatism data 712, and the accommodation data 714. Finally, thediagnostic assistant program considers the history data 716 which thepatient provided when answering the questionnaire 518.

[0303] The diagnostic assistant program, simulating the reasoning of atrained optometrist, will then produce a lens recommendation 718.

[0304] The diagnostic assistant program can also analyse the results ofthe visual testing in order to identify the severity of the visualdisorders at all three layers of the visual process 100, 102, 106.

[0305]FIG. 8 shows a data flow diagram illustrating how the diagnosticassistant program analyses the test data to assess what problems occurin the functional layer 102 and the perceptual layer 106. The program iscomposed of a large number of logical equations organised in modules.The analysis process mirrors that which would be carried out by atrained optometrist. The supervisory module 700 first examines data 706associated with static testing. The results of this analysis areconsidered when analysing data 722 associated with contrast testing. Thesupervisory program 700 also initiates an analysis of the data 724stored during the testing of macular integrity, or in the case where thepatient is a child, saccades data 726. The inferences drawn from theanalysis of data 724 and 726 are combined with the analysis of staticdata 706 and contrast data 722 before analysing data 728 associated withperipheral vision tests. Building on this analysis, the dynamicassistant program proceeds to analyse data 730 associated with thecolour vision test, and then reviews the conclusions reached in thelight of history data 732 collected from the patient when answering thequestionnaire 518. The analysis of data 706, 722, 724, 726, 728, 730 and732 leads to a first set of conclusions 750.

[0306] In a separate data flow path, the supervising module 700initiates an analysis of data 720 derived from dynamic tests. Theanalysis will then in sequence addresses the suppression data 734, thephoria data 736, the fusion data 738, the steropsis data 740 and historydata 742 in order to reach a second set of conclusions 752. Thediagnostic assistant program then combines the first set of conclusions750 with the second set of conclusions 752 in order to produce anassessment of the patient's visual status 744.

[0307] The vision care professional is presented with the data, theoutcome of the analytical process, and comparisons with other patient'scases which can then be used as the basis for their clinical decisions.

[0308] In many jurisdictions there will be laws which specify that thediagnostic analysis of vision problems (the optical layer 100) must becarried out by a licensed optometrist, ophthalmologist or other personas described in the various statutes. Therapy involving drug treatment(required for problems in the functional layer 102 and perceptual layer106) may only be carried out by a registered medical practitioner.

[0309] The optometrist, who will have access to a large database 226 ofclinical results from previous tests, will examine all the results andreach a conclusion which will then be forwarded to the patient.

[0310] If the optometrist believes that there are no problems involvingthe functional or perceptual layer 106 and the diagnosis is likely to bereliable, the optometrist may issue a prescription for spectacles whererequired to correct optical layer problems. The optometrist may alsoissue information about eye exercises.

[0311] If the test results are inconsistent or indicate possibleproblems with the functional laser 102 or perceptual layer 106, thepatient will be advised to see an appropriate professional eye carespecialist in their own locality.

[0312] An important aspect of the lensless flat screen vision testingsystem described herein is mobility. To obtain mobility at realisticcosts it is necessary to separate the eye test measurements from theprofessional vision diagnosis.

[0313] When this lensless flat-screen vision testing system isdisseminated by a network such as the World Wide Web 202, the new visionanalysis system allows the vision testing to be carried out remotely inseveral ways.

[0314] Where there is access to a computer 1901 connected to the Web202, individual patients from anywhere in the world may run the tests bylogging onto a web page 300, thereby freeing themselves from the need totravel and attend a clinic. Where the patients are not fully capable ofrunning the tests by themselves, as a result of disability, age,language or any other problem, they may be assisted by people withoutoptometric training.

[0315] The vision system may alternatively or additionally be used insmall shops or booths as a franchise style of operation. The system canalso enable individual optometrists to set up low-overhead computerbased optometry clinics where the test equipment is rented or leased.

[0316] Where there is no computer access, people without optometrictraining can take lightweight portable computers, such as notebookcomputers, palm computers, combined with the new thin-form lightweightmonitors to patients. These mobile test stations can connect to the Web202 either directly by a wired connection or remotely via a cellulartelephone or satellite telephone connection or other available media. Amobile self-contained unit can provide full diagnostic capabilities,when operated by people with optometric training, as on-the-spotprofessional decisions may be required.

[0317] A supervising optometrist located at a base station cansupervise, via computer, a number of mobile Vision Service Technicians(VST). The VST's can visit patients at preferred locations (for examplehome, office, hospital) and carry out the vision measurement testingusing a similar set of tests as available on the network version of theprogram.

[0318] On arrival at the patient's location, the VST can link viacomputer or cellular telephone to the base station and conduct thevision testing session. The results of each test may be fed back to thebase station on completion.

[0319] The supervising optometrist can thus watch the progress of thetests, answer any queries, request further information and at the end ofthe test forward a diagnosis to the VST for action.

[0320] Since the VST is present at the vision test, he or she will alsobe able to carry out a simple examination of the patient's eyes forpossible functional layer problems and report back to the optometrist atthe base station either by sending an image of the findings or a reporton the observations of any irregularities observed.

[0321] The lensless flat screen vision testing technology may also bedisseminated by the use of franchise operations. The lensless flatscreen vision testing methodology means that routine vision testing maybe carried out using little more than a personal computer and anInternet connection. This suggests the establishment of a new low costvision test centre where several people could be tested simultaneouslyby a single optometrist.

1. A method for testing vision of a human subject, said methodcomprising the steps of: (a) adjusting at least one setting of a displaydevice such that a sequence of graphic objects displayed on said displaydevice conforms to a pre-defined appearance; (b) displaying saidsequence of graphic objects on said display device to test the visualfunctioning of the human subject, (c) recording at least one action ofthe human subject performed in response to the display of said sequenceof graphic objects; (d) calculating from said recorded actions at leastone aspect of the visual functioning of the subject; and (e) calculatingat least one corrective lens prescription for the human subject fromsaid at least one aspect of the visual functioning of the subject.
 2. Amethod as claimed in claim 1, the method comprising the further step of:(f) modifying said sequence of graphic objects based on said at leastone action of the human subject.
 3. A method as claimed in claim 1,wherein each said graphic object relates to at least one visual test ofa set of visual tests able to be performed, and an order in which saidtests are performed is varied such that at least one following test isselected from said set based on a response of the human subject to acurrent one of said tests.
 4. A method as claimed in any one of thepreceding claims, wherein step (a) comprises the sub-steps of: (aa)loading computer executable instructions into a memory means of acomputer connected to said display device; (ab) running a first portionof said computer executable instructions to adjust the black and whitecontrast of said display device to match a predetermined black and whitecontrast; and (ac) running a second portion of said computer executableinstructions to adjust the intensity of at least one colour used in thedisplay of colour images on said display device such that said at leastone colour contained in images displayed on said display device conformsto a corresponding predefined colour.
 5. A method as claimed in any oneof the preceding claims, wherein step (b) comprises the sub-steps of:(ba) displaying a first visual object on said display device such thatsaid first visual object increases in size in the range from apredetermined minimum size to a predetermined maximum size; (bb) haltingthe growth of said first visual object as soon as the human subject,viewing said first visual object from a predetermined distance, is ableto distinguish a feature of said first visual object; and step (c)comprises the sub-step of: (ca) recording the size of said first visualobject when the growth of said first visual object was halted.
 6. Amethod according to claim 5, wherein said predetermined minimum size is2 mm high and said predetermined maximum size is 150 mm high.
 7. Amethod as claimed in claimed in claim 5 or 6, wherein said first visualobject comprises a plurality of black E-shaped characters against awhite background.
 8. A method as claimed in claim 5 or 6, wherein saidfirst visual object comprises a plurality of black C-shaped objects,each of said C-shaped characters being enclosed within a black border.9. A method as claimed in claim 7 or 8, wherein said visual objects aredisplayed on a red coloured background.
 10. A method as claimed in claim7 or 8, wherein said visual objects are displayed on a green colouredbackground.
 11. A method as claimed in any one of the preceding claims,wherein step (b) comprises the further step of: (bd) displaying sets ofstraight lines on said display device, said lines being rotated from thevertical by angles ranging between 0° and 360°; step (c) comprises thestep of: (cb) selecting those of said lines perceived by the humansubject to be darker; and step (d) comprises the step of: (da)calculating an astigmatism of the human subject from said selectedlines.
 12. A method as claimed in claim 11, wherein said straight linesare arranged in a fan shape.
 13. A method as claimed in claim 11,wherein said straight lines are grouped in a plurality of squares witheach line within each said square being substantially parallel to theother lines within said square, the lines for adjacent ones of saidsquares being inclined to each other.
 14. A method as claimed in claim9, wherein straight lines are arranged radially around a central regionand said straight lines are rotated.
 15. A method as claimed in any oneof the preceding claims, wherein step (b) comprises the sub-steps of:(be) initialising a first visual object comprising parallel lines havinga first spatial frequency and being rotated from the vertical by anangle between 0° and 360°; (bf) displaying said first visual object onsaid display device such that a spatial frequency of said parallel linesis progressively decreased from said first spatial frequency; (bg)halting sub-step (bf) when the human subject, viewing said first visualobject from a predetermined distance, is able to distinguish a featureof said first visual object; and step (c) comprises: (cc) recording thespatial frequency of said parallel lines when step (bf) is halted.
 16. Amethod as claimed in claim 15, wherein said first visual object is takenfrom the group consisting of a grey-scale pattern, a red-scale patternand a blue-scale pattern.
 17. A method as claimed in claim 15 or 16,wherein step (d) comprises the sub-steps of: (db) calculating a visualacuity of the human subject; and (dc) from said visual acuity,calculating aspects of spherical and cylindrical lens prescriptioncomponents for the human subject.
 18. A method as claimed in any one ofthe preceding claims, wherein step (b) comprises the sub-steps of: (bh)initialising at least one visual object at a first contrast level, saidat least one visual object having a cyclically varying parameter andbeing rotated from the vertical by an angle between 0° and 360°; (bi)displaying said first visual object on said display device such that acontrast level of said at least one visual object is progressivelyincreased from said first contrast level; (bj) halting sub-step (bi)when the human subject, viewing said first visual object from apredetermined distance, is able to distinguish a feature of said firstvisual object; and step (c) comprises: (cd) recording the contrast levelof said at least one visual object when step (bi) is halted.
 19. Amethod as claimed in any one of the preceding claims, wherein step (b)comprises the sub-steps of: (bk) displaying a fixation object and apositioning object such that said positioning object is in a blind spotof the human subject's vision when the human subject fixates on saidfixation object from a predetermined distance from said display device;(bl) displaying a moving object and a pointer object while the humansubject views said display device from said predetermined distance, saidpointer object being controllable by the human subject to overlay saidmoving object; and (bm) intermittently displaying a peripheral objectwhile the human subject controls said pointer object; and step (c)comprises the sub-step of: (ce) recording a response of the humansubject if the human subject correctly observes said peripheral objectwhile correctly positioning said pointer object over said moving object;and step (d) comprises the sub-step of: (dd) calculating a measure ofsaid subject's peripheral vision from said response.
 20. A method asclaimed in any one of the preceding claims, wherein step (b) comprisesthe sub-steps of: (bn) displaying a fixation object and a positioningobject such that said positioning object is in a blind spot of saidsubject's vision when the human subject fixates on said fixation objectfrom a predetermined distance from said display device; and (bo)displaying a grid object associated with at least said fixation object;step (c) comprises the sub-step of: (cf) recording any irregularities insaid grid object perceived by the human subject when said subject viewssaid grid object from said predetermined distance and the human subjectfixates on said fixation object; and step (d) comprises the sub-step of:(de) calculating a measure of said subject's macula integrity from saidrecorded irregularities.
 21. A method as claimed in any one of thepreceding claims, wherein step (b) comprises the sub-steps of: (bp)displaying a series of objects spaced at irregular intervals andrequesting the human subject to identify said objects; and step (c)comprises the sub-step of: (cg) recording a number of correctidentifications and a total time taken by the human subject to identifysaid objects.
 22. A method as claimed in any one of the precedingclaims, wherein step (b) comprises the sub-step of: (bq) displaying aseries of objects and requesting said subject to identify those of saidobjects that are substantially identical; and step (cc) comprises thesub-step of: (ch) recording a number of correct identifications and atotal time taken by said subject to identify said objects.
 23. A methodas claimed in any one of the preceding claims, wherein step (b)comprises the sub-step of: (br) displaying a sequence of numbers in arandom order, each of said numbers having an associated letter, andrequesting the human subject to locate said numbers in a prescribedorder and to identify the associated letters; and step (c) comprises thesub-step of: (ci) recording a number of correct locations andidentifications and a total time taken by the human subject to locateand identify said sequence.
 24. A method as claimed in any one of claims21 to 23, wherein step (d) comprises the sub-steps of: (df) evaluatingfrom step (c) an ability of the human subject to fixate, refixate andvisually scan objects; (dg) comparing said ability with statistical datarelating expected ability to age.
 25. A method as claimed in any one ofthe preceding claims, wherein step (b) comprises the sub-steps of: (bs)placing a first filter between a first eye of the human subject and saiddisplay device and a second filter between a second eye of the humansubject and said display device; and (bt) displaying a first set ofobjects visible through said first filter but not visible through saidsecond filter, and a second set of objects visible through said secondfilter but not visible through said first filter; step (c) comprises thesub-step of: (cj) recording a total number of objects seen by the humansubject when viewing said display device with both eyes simultaneously;and step (d) comprises the sub-step of: (dh) calculating a measure ofbinocular vision of the human subject from said total number.
 26. Amethod as claimed in any one of the preceding claims, wherein step (b)comprises the sub-steps of: (bu) placing a first filter between a firsteye of the human subject and said display device and a second filterbetween a second eye of the human subject and said display device; and(bv) displaying a first set of objects visible through said first filterbut not visible through said second filter, and at least one moveableobject visible through said second filter but not visible through saidfirst filter, said at least one moveable object being controllable bythe human subject; step (c) comprises the sub-step of: (ck) recordingwhether or not the human subject can align said at least one moveableobject with at least one object from said first set of objects; and step(d) comprises the sub-step of: (di) calculating a measure of alignmentbetween the first eye and the second eye of the human subject.
 27. Amethod as claimed in any one of the preceding claims, wherein step (b)comprises the sub-steps of: (bw) placing a first filter between a firsteye of the human subject and said display device and a second filterbetween a second eye of the human subject and said display device; and(bx) displaying a first object visible through said first filter but notvisible through said second filter, and a second object visible throughsaid second filter but not visible through said first filter, such thatthe human subject viewing said first object and said second objectperceives an image having an identifiable location; (by) moving saidfirst object away from said second object on said display device untilsaid subject no longer perceives said image; step (c) comprises thesub-step of: (cl) recording a separation between said first object andsaid second object when the human subject no longer perceives saidimage; and step (d) comprises the sub-step of: (dj) calculating fromsaid separation a measure of the ability of the human subject to fuseimages.
 28. A method as claimed in any one of the preceding claims,wherein step (ca) comprises the sub-steps of: (ad) displaying one ormore calibration objects on said display device; (ae) comparing a sizeof said one or more calibration objects with a size of a correspondingphysical object; (af) adjusting the size of said one or more calibrationobjects to be substantially the same as the size of the correspondingphysical object; and (ag) calibrating said display device based on saidadjustment.
 29. A method as claimed in claim 28, wherein said physicalobjects are taken from the group consisting of a credit card, a disketteand a 10 cm by 10 cm square.
 30. A method as claimed in any one of thepreceding claims, wherein step (c) comprises the sub-steps of: (ah)displaying a set of objects having a first colour on said display deviceagainst a background having a second colour differing by less than 5%from said first colour; (ai) adjusting at least one source of ambientlight if one or more of said set of objects are not visible when saiddisplay device is viewed from a predefined distance.
 31. An apparatusfor testing vision in a human subject, the apparatus comprising: meansfor adjusting at least one setting of a computer display such that asequence of graphic objects displayed on said computer display conformsto a pre-defined appearance; means for displaying said sequence ofgraphic objects on said computer video display to test the visualfunctioning of said human subject, means for recording at least oneaction of said human subject performed in response to the display ofsaid sequence of graphic objects; means for calculating from saidrecorded actions at least one aspect of the visual functioning of saidsubject; and means for calculating at least one corrective lensprescription for the human subject from said at least one aspect of thevisual functioning of the subject.
 32. A computer program elementcomprising computer program code means to make a computer execute aprocedure to: adjust at least one setting of a video display of saidcomputer such that a sequence of graphic objects displayed on said videodisplay conforms to a pre-defined appearance; display said sequence ofgraphic objects on said video display to test the visual functioning ofsaid human subject, record at least one action of said human subjectperformed in response to the display of said sequence of graphicobjects; calculate from said recorded actions at least one aspect of thevisual functioning of said subject; and calculate at least onecorrective lens prescription for the human subject from said at leastone aspect of the visual functioning of the subject.
 33. A computerreadable medium, having a program recorded thereon, where the program isconfigured to make a computer execute a procedure to: adjust at leastone setting of a video display of said computer such that a sequence ofgraphic objects displayed on said video display conforms to apre-defined appearance; display said sequence of graphic objects on saidvideo display to test the visual functioning of said human subject,record at least one action of said human subject performed in responseto the display of said sequence of graphic objects; calculate from saidrecorded actions at least one aspect of the visual functioning of saidsubject; and calculate at least one corrective lens prescription for thehuman subject from said at least one aspect of the visual functioning ofthe subject.
 34. A system for the testing of vision in a human subject,said system comprising: a) a server having: a first memory for storingan application program and one or more test results from visual testingof a human subject; means for receiving said one or more test results;means for transmitting said application program; means for processingsaid one or more test results to calculate at least one aspect of thevisual functioning of the human subject; and means for calculating atleast one corrective lens prescription for the human subject from saidat least one aspect of the visual functioning of the subject; and b) aclient computer having: a display device for displaying a sequence ofgraphic objects to the human subject; means for receiving saidapplication program; means for running said application program toadjust at least one setting of said display device such that saidsequence of graphic objects displayed on said display device conforms toa pre-defined appearance; means for recording said one or more testresults of the human subject in response to the display of said sequenceof graphic objects; and means for transmitting said one or more testresults to said server.
 35. A method of standardising the appearance ofvisual objects displayed on a video display, the method comprising thesteps of: installing an application program file on a computer;displaying said visual objects on said video display connected to saidcomputer; requesting a person viewing said video display to confirm thesize of at least one of said visual objects; requesting the person toconfirm whether a specified one of said visual objects is visible; andsaid application program file utilising the responses of the person tosaid requests to adjust the relative outputs of the colours used indisplaying said visual objects and the relative dimensions of saidvisual objects.
 36. A method of testing the vision of a human patientcharacterised by displaying to said patient a plurality of interactiveoptical tests using a computerised display device and recording testresults using said computerised display device.
 37. A method formeasuring the vision of a human subject, said method comprising thesteps of: displaying on a display device a first test to check whetherthe vision of said subject is within a measurement range of said method;displaying on said display device a second test to determine a requiredsensitivity of said method; selecting, based on responses of saidsubject to said first and second tests, further tests to display on saiddisplay device to measure an optical power of one or both eyes of saidsubject; wherein said further tests are selected from the groupconsisting of: tests of visual acuity; tests of spherical power; testsof cylindrical power; tests for astigmatism; and tests for near visualacuity; and wherein said subject views said first test, said second testand said further tests without lenses being interposed between saiddisplay device and said subject.
 38. A method as claimed in claim 37,comprising the further step of: calculating a corrective lensprescription based on responses of said subject to said further tests.39. A method as claimed in claim 37 or 38 wherein said subject viewssaid tests from more than one predetermined test distance from saiddisplay device.
 40. A method as claimed in any one of claims 37-39comprising the further step of: displaying on said display devicescreening tests to check for pathological conditions in the vision ofsaid subject.
 41. A method as claimed in any one of claims 37-40 whereinsaid further tests form a sequence of tests in which later tests in saidsequence are selected based on responses of said subject to earliertests in said sequence.